Systems of heart valve delivery

ABSTRACT

A delivery system and method for delivering a prosthetic heart valve to the aortic valve. The system includes a delivery catheter having a steering mechanism thereon for delivering a balloon-expandable prosthetic heart valve to the aortic valve through an introducer passing into the left ventricle through its apex. The introducer may have a more floppy distal section than a proximal section to reduce trauma to the heart wall while preserving good operating field stability. The delivery catheter includes a deflecting segment just proximal to a distal balloon to facilitate positioning of the prosthetic heart valve in the proper orientation. A trigger in a catheter handle may be coupled to a deflection wire that actuates the deflecting segment, while a slider in the handle controls retraction of a valve pusher. The prosthetic heart valve may be installed over the existing calcified leaflets, and a pre-dilation valvuloplasty procedure may also be utilized.

RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.16/703,695, filed Dec. 4, 2019, now U.S. Pat. No. 11,458,014, which is acontinuation of U.S. application Ser. No. 15/662,021, filed Jul. 27,2017, now U.S. Pat. No. 10,500,044, which is a continuation of U.S.application Ser. No. 14/610,982, filed Jan. 30, 2015, now U.S. Pat. No.9,717,594, which is a continuation of U.S. application Ser. No.13/922,129, filed Jun. 19, 2013, now U.S. Pat. No. 8,945,208, which is acontinuation of U.S. application Ser. No. 12/835,546, filed Jul. 13,2010, now U.S. Pat. No. 8,475,522, which claims priority under 35 U.S.C.§ 119(e) to U.S. provisional application No. 61/225,510 filed Jul. 14,2009.

FIELD OF THE INVENTION

The present invention relates to methods and systems used to deliver aprosthetic valve to a heart. More specifically, the present inventionrelates to methods and apparatus for surgically replacing a heart valvewithout opening the chest cavity and with or without placing the patienton bypass, the latter being termed “off-pump.”

BACKGROUND OF THE INVENTION

Heart valve replacement may be indicated when there is a narrowing ofthe native heart valve, commonly referred to as stenosis, or when thenative valve leaks or regurgitates, such as when the leaflets arecalcified. When replacing the valve, the native valve may be excised andreplaced with either a biologic or a mechanical valve. Mechanical valvesrequire lifelong anticoagulant medication to prevent blood clotformation, and clicking of the valve often may be heard through thechest. Biologic tissue valves typically do not require such medication.Tissue valves may be obtained from cadavers or may be porcine or bovine,and are commonly attached to cloth-covered synthetic rings and/orleaflet support frames that are secured to the patient's heart valveannulus.

Conventional heart valve surgery is an open-heart procedure conductedunder general anesthesia. An incision is made through the patient'ssternum (sternotomy), and the patient's heart is stopped while bloodflow is rerouted through a heart-lung “cardiopulmonary” bypass machine.Valve replacement surgery is a highly invasive operation withsignificant concomitant risks include bleeding, infection, stroke, heartattack, arrhythmia, renal failure, adverse reactions to the anesthesiamedications, as well as sudden death. Fully 2-5% of patients die duringsurgery. Post-surgery, patients temporarily may be confused due toemboli and other factors associated with the heart-lung machine. Thefirst 2-3 days following surgery are spent in an intensive care unitwhere heart functions can be closely monitored. The average hospitalstay is between 1 to 2 weeks, with several more weeks to months requiredfor complete recovery.

In recent years, advancements in “minimally-invasive” surgery andinterventional cardiology have encouraged some investigators to pursuepercutaneous replacement of the aortic heart valve. Percutaneous ValveTechnologies (“PVT”), formerly of Fort Lee, N.J. and now part of EdwardsLifesciences of Irvine, Calif., has developed a plastically- orballoon-expandable stent integrated with a bioprosthetic valve. Thestent/valve device, now called the Edwards Sapien™ Heart Valve, isdeployed across the native diseased valve to permanently hold the valveopen, thereby alleviating a need to excise the native valve. The EdwardsSapien™ Heart Valve is designed for delivery in a cardiaccatheterization laboratory under local anesthesia using fluoroscopicguidance, thereby avoiding general anesthesia and open-heart surgery.The Sapien™ Heart Valve may be inserted transfemorally with theRetroFlex™ delivery system, or transapically with the Ascendra™ deliverysystem. A description of the Ascendra™ delivery system is provided inU.S. Patent Publication No. 2007-0112422 to Dehdashtian.

Other prior art minimally-invasive heart valves use self-expandingstents as anchors. In the percutaneous/endovascular aortic valvereplacement procedure, accurate placement of the prosthetic valverelative to the coronary ostia is critical. Though the proximal end ofthe stent is not released from the delivery system until accurateplacement is verified by fluoroscopy, the self-expanding stent may stilljump once released. It is therefore often difficult to know where theends of the stent will be with respect to the native valve andsurrounding structures.

U.S. Pat. No. 6,425,916 to Garrison et al. describes a two-piece devicefor replacement of the aortic valve that is adapted for delivery througha patient's aorta. A stent is endovascularly placed across the nativevalve, then a replacement valve is positioned within the lumen of thestent and connected thereto. By separating the stent and the valveduring delivery, a so-called “two-stage” approach, the profile of thedelivery system can be reduced. Both the stent and a frame of thereplacement valve may be balloon- or self-expandable.

Some researchers propose implanting prosthetic heart valves at theaortic annulus through a ventricular approach. For instance, ChristophH. Huber of the Brigham and Women's Hospital of Harvard Medical School,and others, have proposed a procedure in which a self-expanding valvestent is implanted at the aortic position using a direct-accesstransapical approach. (E.g., Huber, et al. Direct-access valvereplacement a novel approach for off-pump valve implantation usingvalved stents. J Am Coll Cardiol 2005; 46:366-70). The clinical studiesby Huber, et al. recommend use of the procedure only for animals withnormal, noncalcified leaflets. More recently, Bergheim in U.S. PatentPublication No. 2005/0240200 discloses another transapical approach inwhich either a balloon- or self-expanding valve may be implanted, andalso proposes removing or decalcifying stenotic valves. Suchdirect-access or “port access” techniques though less invasive thanconventional open heart surgery are not called, “minimally-invasive,” asthat term is now primarily used to refer to valves delivered usingelongated catheters via the vasculature (i.e., endovascularly).

In view of drawbacks associated with previously known techniques forreplacing a heart valve without open-heart surgery or cardiopulmonarybypass, i.e., minimally-invasive procedures, improved methods andapparatuses that are more robust and even less invasive are needed.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide a heart valvedelivery system for delivery of a prosthetic (i.e., replacement) heartvalve to a native valve site without an open chest procedure. Thedelivery system includes a valve delivery catheter having a steerablesection to facilitate positioning of the valve.

In accordance with one embodiment of the present application, a medicalcatheter introducer includes an elongated tubular sheath extendingdistally from a proximal housing and containing at least one introducervalve for fluidly sealing around a catheter. The sheath has a proximalsegment with a first stiffness extending a length L of at least one halfthe length of the sheath, and a distal section with a second stiffnessless than the first stiffness and having a length l. Desirably, thelength l of the distal section ranges between about 4-12 cm. In oneembodiment, the length L of the proximal segment is at least 24 cm, andthe length l of the distal section ranges between about 6-9 cm. Also,the tubular sheath may have an inner liner and a reinforcing coil thatboth extend the entire length, and at least two sections of outer tubesin series having different durometers that create the differingstiffnesses of the sheath.

Another aspect disclosed herein is a medical introducer and heart valvedelivery catheter combination comprising a delivery catheter having adistal balloon of sufficient diameter to expand a crimped heart valvethereon. An introducer that receives the delivery catheter therethroughhas an elongated tubular sheath extending distally from a proximalhousing. The proximal housing contains at least one introducer valve forfluidly sealing around a proximal length of the delivery catheter. Thesheath further includes a proximal segment with a first stiffnessextending a length L of at least one half the length of the sheath, anda distal section with a second stiffness different than the firststiffness and a length l. A tubular loader defines a throughbore thatreceives a distal portion of the delivery catheter, the tubular loaderhaving structure for engaging mating structure on a proximal end of theintroducer housing and a distal nose that extends through and opens theintroducer valve and facilitates passage therethrough of the balloon ofthe delivery catheter.

A still further feature of the present application is a medicalintroducer and heart valve delivery catheter combination, comprising adelivery catheter having a distal balloon of sufficient diameter toexpand a crimped heart valve thereon. The catheter includes a markerband at a proximal end of the balloon, and a tubular valve pusher thatmoves longitudinally with respect to the balloon and has a distal markerband. An introducer having an elongated tubular sheath extendingdistally from a proximal housing contains at least one introducer valvefor fluidly sealing around a proximal length of the delivery catheter.The introducer sheath has a throughbore for passage of the deliverycatheter and a marker dot array around its distal tip to distinguish thedistal tip from the marker bands of the balloon and the pusher.

In accordance with a still further aspect, a medical introducer andheart valve delivery catheter combination comprises a delivery catheter,an introducer, and a tubular loader therebetween. The delivery catheterhas a distal balloon of sufficient diameter to expand a crimped heartvalve thereon. The introducer has an elongated tubular sheath extendingdistally from a proximal housing which contains at least one introducervalve for fluidly sealing around a proximal length of the deliverycatheter. Finally, the tubular loader includes a throughbore thatreceives a distal portion of the delivery catheter, structure forengaging mating structure on a proximal end of the introducer housing,and a distal nose that extends through and opens the introducer valve,facilitating passage therethrough of the balloon of the deliverycatheter. The loader also has a proximal housing with a seal for fluidlysealing around the introducer sheath, and a single-handed vent foraspirating air from within the loader.

A heart valve delivery catheter of the present application includes acatheter tube having a distal balloon thereon of sufficient diameter tofully expand a crimped heart valve from within. The balloon is disposedon the end of a deflectable portion of the catheter tube actuated by adeflection pull wire. The delivery catheter further includes a tubularvalve pusher that slides over the catheter tube and moves longitudinallywith respect to the balloon. The delivery catheter also has a proximalcontrol handle on which are mounted both a deflection actuator fordeflecting the deflectable portion of the catheter tube and a pusheractuator for displacing the valve pusher. Preferably, the deliverycatheter includes a plurality of concentric tubes extending from withinthe control handle, and at least one passive seal within the handle forsealing around one of the tubes without preventing its movement.

Another benefit of the present application is a medical introducer andheart valve delivery catheter combination that comprises a deliverycatheter having a catheter tube with a distal balloon thereon ofsufficient diameter to fully expand a crimped heart valve from within.An introducer has an elongated tubular sheath extending distally from aproximal housing which contains at least one introducer valve forfluidly sealing around a proximal length of the delivery catheter. Atubular loader defines a throughbore that receives a distal portion ofthe delivery catheter, and includes structure for engaging matingstructure on a proximal end of the introducer housing and a distal nosethat extends through and opens the introducer valve and facilitatespassage therethrough of the balloon of the delivery catheter. The loaderhas a proximal housing with a loader seal for fluidly sealing around theintroducer sheath, and a single-handed vent for aspirating air fromwithin the loader.

A heart valve delivery catheter and heart valve combination disclosedherein features an expandable prosthetic heart valve having a crimpedconfiguration and proximal and distal ends. A delivery catheter includesa catheter tube with a distal balloon thereon of sufficient diameter tofully expand the crimped heart valve from within. The balloon has alength greater than the length of the heart valve so as to have proximaland distal exposed portions, and the balloon is folded in a manner thatleaves only longitudinal fold lines to contrast with the ends of theheart valve under echocardiography.

A heart valve delivery catheter of the present application a deliverycatheter having a catheter tube with a distal balloon thereon ofsufficient diameter to fully expand the crimped heart valve from within,the balloon being disposed on the end of a deflection tube actuated by adeflection pull wire, the deflectable portion comprising a braidedstructure and the deflection wire extending along its length up to adistal coil to which the deflection wire attaches, the deflectableportion having a dimension no greater than 8 French.

A further understanding of the nature and advantages of the presentinvention are set forth in the following description and claims,particularly when considered in conjunction with the accompanyingdrawings in which like parts bear like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the present invention will become appreciatedas the same become better understood with reference to thespecification, claims, and appended drawings wherein:

FIG. 1 is a schematic frontal view of a patient showing the location ofan intercostal incision providing access to the apex of the leftventricle of the heart;

FIGS. 2A-2B are cross-sectional views through the left side of apatient's heart showing a procedure for dilating a calcified aorticannulus prior to implantation of a prosthetic heart valve in accordancewith the present invention;

FIGS. 3A-3E are cross-sectional views through the left side of apatient's heart showing several steps in a procedure for implanting aprosthetic heart valve in accordance with the present invention;

FIG. 4 is an exploded perspective view of an introducer/dilatorcombination used in the port access heart valve implantation procedureof the present invention;

FIG. 4A is an assembled view of the introducer/dilator combination ofFIG. 4 ;

FIGS. 5A and 5B are exploded perspective and elevational views of theintroducer of FIG. 4 ;

FIG. 6A is a plan view of the introducer of FIG. 4 ;

FIG. 6B is a longitudinal sectional view of the introducer taken alongline 6B-6B of FIG. 6A;

FIGS. 6C and 6D are enlarged views portions of a variable flexibilitysheath of the introducer of FIG. 6B;

FIG. 7 is a perspective view of an exemplary balloon catheter/loaderassembly for implanting a prosthetic heart valve as disclosed herein;

FIG. 7A is an exploded perspective view of a loader that provides aninterface between the introducer of FIGS. 4-6 and the balloon catheterof FIG. 7 ;

FIG. 8 is a broken elevational view of the balloon catheter of FIG. 7 ;

FIG. 9 is a longitudinal sectional view of a proximal control handle ofthe balloon catheter of FIG. 7 ;

FIGS. 10A and 10B are exploded views of the proximal control handle ofFIG. 9 ;

FIG. 11 is an enlarged sectional view of a distal deflecting segment ofthe balloon catheter of FIG. 7 , also showing a distal balloon in adeflated state within a protective sheath;

FIG. 12 is an enlarged sectional view of a distal balloon of the ballooncatheter of FIG. 7 in its inflated state;

FIG. 13 is an exploded view of the balloon catheter and introducer (insection) combination prior to coupling with a heart valve crimped ontothe balloon;

FIG. 14A is an assembled view of the balloon catheter and introducer (insection) combination after insertion of the balloon catheter through theintroducer;

FIGS. 14B-14E are views similar to FIG. 14A showing use of the heartvalve delivery system disclosed herein in situ at the occurrence of aseries of steps in a valve implant procedure;

FIG. 15 is a longitudinal sectional view of a distal end of an exemplaryballoon catheter showing a prosthetic heart valve crimped over a balloonfolded in a way that enhances visualization of the valve during implant;

FIG. 16 is a radial section of the folded balloon of FIG. 15 ; and

FIG. 17 is a radial section of the balloon of FIG. 16 illustrating apreferred folding technique.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The heart is a hollow muscular organ of a somewhat conical form; it liesbetween the lungs in the middle mediastinum and is enclosed in thepericardium. The heart rests obliquely in the chest behind the body ofthe sternum and adjoining parts of the rib cartilages, and projectsfarther into the left than into the right half of the thoracic cavity sothat about one-third is situated on the right and two-thirds on the leftof the median plane. The heart is subdivided by septa into right andleft halves, and a constriction subdivides each half of the organ intotwo cavities, the upper cavity being called the atrium, the lower theventricle. The heart therefore consists of four chambers; the right andleft atria, and right and left ventricles.

As seen in FIG. 1 , the left ventricular apex LVA is directed downward,forward, and to the left (from the perspective of the patient). The apextypically lies behind the fifth left intercostal space (or between thefourth and fifth), 8 to 9 cm from the mid-sternal line, and about 4 cmbelow and 2 mm to the medial side of the left mammary papilla. Access tothe left ventricle may therefore be attained through an intercostalincision 20 as shown in dashed line, positioned over the fifth leftintercostal space. Such an approach is often termed a“mini-thoracotomy,” and lends itself to surgical operations on the heartcarried out using one or more short tubes or “ports”—thus, theoperations are often referred to as “port-access” procedures.

In a preferred embodiment of the present invention, a surgeon implants aprosthetic heart valve over the existing native leaflets, which aretypically calcified. There are procedures and devices for removingcalcified leaflets, but the risks associated therewith, including arelease of calcific material into the bloodstream, are notinsignificant. Therefore, a heart valve replacement procedure thatinstalls the prosthetic heart valve directly over and contains thenative leaflets is preferred.

Those skilled in the art will recognize that it may be necessary topre-dilate the leaflets and annulus of the stenotic aortic valve beforedeploying a prosthetic valve within the aortic valve. FIGS. 2A and 2Bare two snapshots of a valvuloplasty procedure that may be initiallyperformed to compress the native aortic heart valve leaflets outwardagainst the sinuses and ascending aorta. As mentioned above, the nativeaortic valve leaflets may be substantially calcified, and thevalvuloplasty may be necessary to crack and otherwise force aparthardened tissue. Pre-dilation increases the flow area through the aorticvalve and creates an opening in the leaflets of sufficient size toreceive the prosthetic valve. Pre-dilatation is preferably achievedusing an expandable member, such as a dilatation balloon catheter. Oneexample of pre-dilation of a valve annulus is seen in U.S. Pat. No.6,908,481 to Cribier, issued Jun. 21, 2005 and expressly incorporated byreference herein.

FIG. 2A illustrates introduction of a guidewire 30 through a pre-formedapical puncture 32 in the left ventricle LV. A distal tip 34 of theguidewire 30 extends through the native aortic valve AV and into theascending aorta AA. The distal tip 34 may extend further over the aorticarch, as seen in FIG. 2B, but the minimum extension is across the aorticvalve AV.

FIG. 2B illustrates an introducer sheath 38 inserted into the LV throughthe apical puncture 32, with a balloon catheter 40 having a dilatationballoon 42 on a distal end passed over the guidewire 30 and through thesheath. As is known, prior to insertion of the sheath 38, a dilatorhaving a gradually tapered tip (not shown) may first be inserted overthe guidewire to enlarge the apical puncture 32. It should be noted atthis point that the surgeon installs one or more purse-string sutures 44in the tissue of the left ventricular apex surrounding the puncture 32.These sutures 44 are pre-implanted prior to formation of the initialpuncture. In a preferred embodiment, the surgeon places a first line ofpurse-string sutures generally in a first circle in one direction, andthen places a second line of purse-string sutures generally in a circleconcentric to the first circle but in an opposite direction. The resultis two concentric circles of separate purse-string sutures 44 defining aperiphery within which the puncture is formed. The purse-string sutures44 can therefore be pulled to cinch the ventricular tissue aroundwhatever object passes through the puncture. In particular, thepurse-string sutures 44 are tightened around both the guidewire 30 andintroducer sheath 38. Installing the separate lines of purse-stringsutures 44 in opposite directions helps prevent tearing of theventricular tissue and provides a more uniform compression aboutwhatever elongated object passes through the puncture.

As indicated in FIG. 2B, the dilatation balloon 42 expands radiallyoutward into contact with the native aortic valve leaflets. Withinformation concerning the size of the particular aortic valves, theballoon 42 is chosen so that it expands outward and nominally compressesthe aortic valve leaflets against the surrounding aortic walls. Thereare various means for assessing the size of the particular patient'saortic valve, including ultrasound, which will not be described herein.Suffice it to say that following the valvuloplasty procedure seen inFIG. 2B, the native aortic valve leaflets are compressed outward againstthe aortic wall and a substantially circular orifice results. Additionaldetails regarding pre-dilatation and valve replacement can be found inApplicant's U.S. Pat. No. 6,908,481 to Cribier, expressly incorporatedby reference herein.

With reference now to FIGS. 3A-3E, a preferred method of deploying andimplanting a prosthetic heart valve of the present invention using atransapical approach will now be described in more detail. The devicesand methods disclosed herein are particularly well-suited for replacinga stenotic aortic valve, and as such that the pre-dilation procedureseen in FIGS. 2A-2B typically precedes the valve implantation so as tosmooth out the contours of the annulus and leaflets. It should be noted,however, that the procedure described herein may be performed withoutvalve pre-dilation.

Furthermore, the present procedure may be performed as a first timevalve implant or to supplement a previous implant. A relatively largeproportion of recipients of prosthetic heart valves are older, typicallyolder than 60. Over time, prosthetic heart valves have been known toshow reduced performance and even failure. Re-operating onseptegenarians and even octogenarians is problematic. However, a portaccess procedure such as disclosed herein eliminates open-heart surgeryand potentially cardiopulmonary bypass, and is therefore more desirablefor the aging patient. Therefore, the present invention contemplatestransapical implantation of a prosthetic heart valve over an existingprosthetic valve implant. In such a case, a pre-dilation step istypically not necessary, though it is conceivable.

Prior to a discussion of the procedure itself, it should be noted that apreferred delivery system of the present invention will be described ingreater detail below with reference to FIGS. 4-13 . The workings of thepresent delivery system may be more easily understood after anexplanation of the steps taken to ultimately implant the valve in theaortic annulus.

The prosthetic heart valve implantation procedure described herein maybe performed in conjunction with cardiopulmonary bypass, or withoutbypass in a so-called off-pump procedure. The necessity for bypassdepends on a number of factors, including the patient's age,vulnerability to such a procedure, and viability of the native leaflets.Ideally, the implantation procedure is performed off-pump.

The surgeon or cardiologist first sizes the aortic valve using aphysical sizer, or with echocardiography. The physician or operatingroom staff then crimps an expandable prosthetic valve 50 over theballoon 52 of a balloon catheter 54 (some of the elements presentlydescribed can be seen in the procedure drawings of FIGS. 3A-3E, whileothers can be seen in the system drawings of the FIGS. 4-13 ). Thesurgeon advances the balloon catheter 54 over a guidewire 60 (that mightbe the same guidewire 30 used in a pre-dilation procedure), through anintroducer sheath 70 that has been inserted through the left ventricularapex puncture 32 with the help of a dilator 74 (sometimes also referredto as an introducer).

The same purse-string sutures 44 that were used for the pre-dilationprocedure may also be used to seal the ventricular tissue around theintroducer sheath 70. In the absence of the pre-dilation procedure, thepurse-string sutures 44 are pre-implanted prior to formation of theinitial puncture. As before, the surgeon places a first line ofpurse-string sutures generally in a first circle in one direction, andthen places a second line of purse-string sutures generally in a circleconcentric to the first circle but in an opposite direction. The resultis two concentric circles of separate purse-string sutures 44 defining aperiphery within which the puncture is formed, and which seal around theintroducer sheath 70.

Furthermore, the dilator 74 that expands the inner diameter of thepuncture 32 and rides over the guidewire 60 may be inserted prior to orwith the introducer sheath 70. Preferred dilator diameters range between12 and 22 French. The introducer sheath 70 comprises the distal end ofan introducer that will be described below. Introducer sheath diametersof no greater than 24 French, and desirably 22 or 24 Fr are preferred.

FIG. 3A shows the introducer sheath 70 passing into the left ventriclethrough the puncture 32 and over the guidewire 60 that extends upwardthrough the calcified aortic valve AV. The surgeon locates a distal tip72 of the introducer sheath 70 just to the inflow side of the aorticvalve AV, as seen in FIG. 3A. At this point, it should be understood bythose of skill in the art that the position of the introducer sheath 70relative to the aortic valve AV, as well as the position of otherelements of the system, is monitored using radiopaque markers andfluoroscopy, or using other imaging systems such as transesophagealecho, transthoracic echo, intravascular ultrasound imaging (IVUS), or aninjectable dye that is radiopaque. A specific combination of suchmarkers for the exemplary system will be described below.

FIG. 3B shows the advancement of the balloon catheter 54 over theguidewire 60 and through the introducer sheath 70. Ultimately, as seenin FIG. 3C, the prosthetic heart valve 50 is located at the aorticannulus and between the native aortic leaflets. FIG. 3C also illustratesretraction of the introducer sheath 70 from its more forward position inFIG. 3B to permit balloon inflation/valve expansion. Radiopaque markersmay be provided on the distal tip 72 of the introducer sheath 70 to moreaccurately determine its position relative to the valve 50 and balloon52.

Again, the precise positioning of the prosthetic heart valve 50 may beaccomplished by locating radiopaque markers on its distal and proximalends, or in-between, for example at a midpoint. Desirably, the surgeoncan adjust the position of the valve 50 by actuating a steering ordeflecting mechanism within the balloon catheter 54, as will bedescribed below. Furthermore, the rotational orientation of the valve 50can be adjusted relative to the cusps and commissures of the nativeaortic valve by twisting the balloon catheter 54 from its proximal endand observing specific markers on the valve (or balloon catheter) underfluoroscopy. One of the coronary ostia 80 opening into one of thesinuses of the ascending aorta is shown, and those of skill in the artwill understand that it is important not to occlude the two coronaryostia with the prosthetic valve 50. It should also be noted thatalthough the native leaflets of the aortic valve AV are shown coaptingin FIG. 3A, and being flexibly displaced by the balloon catheter 54 inFIGS. 3B and 3C, they may actually be compressed further outward againstthe aortic annulus from a pre-dilation procedure.

FIG. 3C shows the prosthetic heart valve 50 in its contracted orunexpanded state crimped around the balloon 52. When the surgeon issatisfied of the proper positioning and rotational orientation of thevalve 50, the balloon 52 is expanded as seen in FIG. 3D. Proper sizemeasurement of the native aortic valve AV enables the surgeon to selectan optimum-sized valve 50 such that it expands outward into good contactwith the aortic annulus. The term “good contact” implies sufficientcontact to ensure that the prosthetic heart valve 50 does not migrateafter implant. Excessive expansion of the valve, however, may damagesurrounding tissue or interfere with the performance of adjacent valves.

A number of devices are available to assist in anchoring the prostheticvalve 50 into the aortic annulus, such as barbs and the like. Apreferred configuration of prosthetic heart valve 50 for use with thepresent invention is disclosed in co-pending U.S. patent applicationSer. No. 12/480,603 to Hariton, filed Jun. 8, 2009, which disclosure isexpressly incorporated herein by reference. Another valve is disclosedin U.S. Pat. No. 7,276,078 to Spenser, filed Jun. 30, 2004, whichdisclosure is also expressly incorporated herein by reference. Ofcourse, the valve 50 can take a variety of different forms but generallycomprises an expandable stent portion that supports a valve structure.The stent portion has sufficient radial strength to hold the valve atthe treatment site and resist recoil of the stenotic valve leaflets.Additional details regarding preferred balloon expandable valveembodiments can be found in U.S. Pat. Nos. 6,730,118 and 6,893,460, bothto Spenser and both of which are expressly incorporated herein byreference. The preferred prosthetic heart valve 50 includes sufficientirregularity on its outer surface such that it may be anchored in theaortic annulus without the use of barbs or other tissue piercingstructure.

Once the valve 50 is properly implanted, as seen in FIG. 3D, the surgeondeflates the balloon 52, and withdraws the entire delivery systemincluding the balloon catheter 54 over the guidewire 60. The introducersheath 70 is then withdrawn, followed by the guidewire 60. Ultimately,the purse-string sutures 44 previously described are cinched tight andtied to close the puncture 32, as seen in FIG. 3E.

It is important to recognize that the heart valve delivery system of thepresent invention is particularly well-suited for the antegrade, leftventricular apex, “transapical,” approach. More particularly, themini-thoracotomy approach requires relatively short instruments.Therefore, the portion of the introducer sheath 70 that extends into thebody is desirably no more than about 8 inches (20 cm) long, and thelength of the balloon catheter 54 that may extend into the introducersheath 70, i.e., the “working length,” is desirably no more than about24 inches (61 cm). Further specifics on the relatively short length ofthe balloon catheter 54 and introducer sheath 70 will be provided below.The short length of the prosthetic heart valve delivery system describedherein is also well-suited for other anatomical approaches, includingthrough the carotid or subclavian arteries. The short length of thesystem is desirable because it enhances controllability and steerabilityof the distal end, relative to longer systems, which helps improveaccuracy and reduced time for valve positioning.

The delivery system of the present invention essentially comprises anintroducer 100, the balloon catheter 54, and attendant couplers andoperating structures, including a loader 140 between the introducer andballoon catheter as seen in FIG. 7 . The introducer 100 is illustratedin FIGS. 4-6 , while the balloon catheter 54 and loader 140 are shown inFIGS. 7-12 . It should be noted that the delivery system is similar toanother system used to percutaneously implant a prosthetic aortic valve,which is disclosed in co-pending U.S. Patent Publication No.2007-0005131 to Taylor, filed Jun. 13, 2005, and expressly incorporatedherein by reference. The present system differs in several aspects thatmake it more suitable for a transapical, port-access, or direct-accessapproach, although some features are common.

As seen in FIGS. 4 and 4A, the introducer 100 comprises theaforementioned distal sheath 70 coupled to an introducer housing 102containing a series of valves. The exploded views of FIGS. 5A and 5Bshows an end cap 104 detached from the introducer housing 102. The endcap 104 includes a flanged nipple 105 for mating with the loader 140, aswill be explained below. The end cap 104 threads or otherwise attachesto the housing 102 and retains therein, in series from proximal todistal, a cross-slit valve 106, a disk valve 108, a spacer 110, and aduck-bill valve 112. These three valves function to provide a seal whenno instruments pass through the introducer 100, and when severaldifferent sizes of instruments pass therethrough. For example, thevalves seal around both the guidewire 60 and the balloon catheter 54 aspreviously shown. The introducer sheath 70 extends into the body vessel,with the introducer housing 102 located outside the body vessel. In apreferred embodiment, the introducer sheath 70 possesses an externalhydrophilic coating and has a length of between about 20-24 cm so thatit may extend through the access incision 20 (see FIG. 1 ), into theleft ventricle and reach the aortic annulus.

As seen best in FIGS. 5 and 5A, the introducer sheath 70 attaches to thehousing 102 via a sealing extension 122 that mates with a distal nipple124 extending from the housing 102. Preferably adhesive is used betweenthese two mating sections. A threaded nut 126 rides over the sheath 70and couples to threading 128 provided on the housing 102 just proximalto the nipple 124. In this way, the various components can bemanufactured (typically molded or extruded) separately and easilycoupled together during assembly. Adhesive may be applied to thethreading 128 prior to coupling the nut 126 for a more secure finalassembly.

A side port tube 130 extends at an angle away from the introducerhousing 102 and terminates in a three-way stopcock 132. This permits theuser to infuse medicaments or other fluids through the lumen of theintroducer 100 even if devices such as the balloon catheter 54 arepresent therein.

FIGS. 6A-6D show further details of the introducer 100, including aseries of depth markings 133 on a distal section of the sheath 70. Themarkings 133 indicate the distance in millimeters from the distal tip 72so that the depth to which the distal tip extends into the leftventricular apex can be easily seen.

FIGS. 6B and 6C illustrate an advantageous construction in which thesheath 70 has greater flexibility along a distal section than along aproximal section. Specifically, the sheath 70 includes a distal section134 having a length l that is more flexible than a proximal section 135,wherein the free length of the sheath 70 is L (extending from thethreaded nut 126). FIG. 6C shows the internal construction of the sheath70, which includes an inner tubular liner 136, a reinforcing coil 137, adistal exterior tube 138 and a proximal exterior tube 139. The liner 136and coil 137 extend the free length L of the sheath 70, while theexterior tubes 138, 139 abut in series. The stiffness of the proximalexterior tube 139 is desirably greater than that of the distal exteriortube 138 to provide the differing flexibilities. Although two discretesections each with constant stiffness are shown, the flexibility may bevaried in more than two sections, and more gradually, with similarresults.

By providing a more flexible distal section 134, movement of the heartmuscle surrounding the introducer sheath 70 (such as in the position ofFIG. 3D) is accommodated with less trauma to the heart tissue. That is,the preferred procedure is with a beating heart with the left ventriclecontinually contracting and relaxing, which creates a significant amountof tissue/introducer movement. Permitting the distal end of theintroducer to flex, or be floppy, helps reduce damage to the heart wall.Moreover, the surgeon often manipulates the catheter or introducer forbetter implant site access, which with a stiffer sheath may cause traumato the heart wall. At the same time, the stiffer proximal section 135ensures that the introducer 100 projects out from the operating field ina relatively straight line, with minimal floppiness, which is desired bysurgeons. Sometimes a stabilizer at the point of incision may be used,which reduces the heart wall movement, though the floppy distal end ofthe sheath still provides a benefit.

The liner 136 provides a smooth inner surface through which the ballooncatheter with heart valve may pass without hindrance, and the coil 137provides hoop strength to the tubular structure to prevent kinking. Thesheath 70 may be fabricated using a number of tube forming techniques,such as extrusion.

In one embodiment, the free length L of the sheath 70 is between about20-24 cm, while the distal section 134 has a length l of between about 4cm and one half the free length L. More preferably the distal section134 has a length l of between about 6-9 cm, and most preferably about 9cm. The length l should be sufficient to permit the floppy portion ofthe sheath 70 to extend at least 4 cm into the heart wall.

In an exemplary embodiment, the inner liner 136 and exterior tubes 138,139 are formed of the same material for better melding, while the coil137 is metallic. One particular combination is the liner 136 andexterior tubes 138, 139 made of a nylon block copolymer sold under thetradename PEBAX®, while the coil 137 is stainless steel. The commercialPEBAX polymers consist of polyether blocks separated by polyamideblocks. The polyether blocks may be based upon polyethylene glycol,polypropylene glycol, or polytetramethylene ether glycol. The polyamidesare usually based upon nylon-11 but may be based upon nylons 6 ofnylon-6,6 or even a copolymer such as nylon-6/nylon-11. The polymersrange in hardness as measured in durometer from Shore A 60 to Shore D72,and the proximal exterior tube 139 has a greater durometer than thedistal exterior tube 138. A selection of PEBAX compositions and theirrespective physical properties are provided on the website,www.pebax.com, in particular under the link, “Medical Applications.”PEBAX® is a registered trademark of Arkema Inc. of Paris, France, withU.S. Corporate offices in Philadelphia, Pa.

FIG. 6D also shows an advantageous visualization system for the distaltip 72 of the introducer sheath 70. A circular array of marker dots 73at the distal tip 72 can be seen under fluoroscopy, and in clearcontrast to marker bands provided on the balloon catheter 54, asexplained below.

FIG. 7 illustrates in perspective the balloon catheter 54, whichcomprises an assembly of interrelated components commencing on aproximal end with a luer fitting 142 and terminating at a distal end ina soft tip 144. The balloon catheter 54, also shown in plan, sectional,and exploded views in FIGS. 8-12 , comprises a control handle 150 havingthe luer fitting 142, a balloon inflation connector 152, a deflectionactuator 154, and a pusher actuator 156. A pusher body 158 extends fromthe handle 150 around a balloon deflection tube 160 having theexpandable balloon 52 located just proximal to the soft tip 144. FIG. 7illustrates a balloon sheath 161 covering the balloon 52 which protectsthe balloon during shipping and is removed prior to use of the system.An elongated stationary protective sleeve 162 also extends from thehandle 150 over a majority of the pusher body 158 and forms an exteriorsurface of the balloon catheter 54 along much of its length. The loader140 shown in perspective in FIG. 7A will be described in more detailbelow and provides a coupling between the balloon catheter 54 and theabove-described introducer 100.

As mentioned, the present application discloses an advantageousvisualization system for the distal tip 72 of the introducer sheath 70.Specifically, at least one marker band will be provided on the proximalend of the balloon 52, and also on a distal end of the pusher body 158.The axial proximity of the distal end of the pusher body 158 and theproximal end of the balloon 52 can therefore be easily seen tofacilitate their engagement. In addition, the circular array of markerdots 73 at the distal tip 72 of the introducer sheath 70 clearlycontrasts with the marker bands on the balloon catheter 54 and thepusher body 158, and helps the surgeon ensure that the introducer hasbeen retracted far enough at the time of valve positioning and balloonexpansion.

Prior to a detailed description of the exemplary balloon catheter 54,its interaction with the introducer 100 via the loader 140 will beexplained. As seen in FIG. 7A, the loader 140 has a generally tubularbody 172 and a slightly externally tapered distal nose 174 that fitswithin the introducer 100, and specifically through the series of valves106, 110, 112 shown in FIG. 6B. The loader body 172 includes a pair ofattached cantilevered fingers 176 extending longitudinally withinternally facing snap ridges for securing the loader 140 to a nipple onthe proximal end cap 104 of the introducer 100. The loader 140facilitates introduction of the balloon catheter 54 into the introducer100. As described above, the introducer housing 102 contains the seriesof valves 106, 110, 112 that in aggregate provide an effective fluidseal against egress of blood through the introducer 100 in the presenceor absence of different sized medical implements. The distal nose 174 ofthe loader 140 extends through the introducer housing 102 and throughthese valves 106, 110, 112 (see FIG. 14A) to hold them open and providea smooth internal lumen which matches the size of the lumen of theintroducer sheath 70. In this way, the somewhat irregular contours ofthe balloon catheter 54 having a prosthetic valve 50 crimped around theballoon 52 may smoothly pass into the introducer sheath 70.

A loader seal, seen exploded in FIG. 7A, positioned within a proximalhousing 178 comprises a pair of annular washers 180 and a resilient ventmember 182. As seen in FIG. 7 , the protective sleeve 162 passes throughthe loader 140, and the loader seal prevents fluid from escaping aroundthe sleeve. The vent member 182 includes a pair of lateral buttons 184that project through apertures in the side of the proximal housing 178.Inward depression of one or both buttons 184 causes deformation of thevent member 182, which in turn opens the distal space within the loaderbody 172 to the atmosphere. Any air entrained in the blood within theloader body 172 can thus easily be vented with one hand. The one-handedaspiration is both more convenient and also helps avoid inadvertentmisalignment of the heart valve from unscrewing a valve cap to vent, atwo-handed operation, which is the conventional arrangement. Moreover,eliminating the previous threaded cap arrangement for tightening aresilient seal with the passive loader seal means that movement of theprotective sleeve 162 (and delivery catheter 54) is never prevented bythe loader valve. In this way, movement of the catheter 54 is decoupledfrom the loader 140 and attached introducer 100.

Prior to balloon expansion as seen in FIG. 12 , the loader 140 couplesover the distal extent of the balloon catheter 54, as seen in FIG. 7 .The distal nose 174 inserts into the introducer housing 102 and thecantilevered loader fingers 176 mate with the flanged nipple of the endcap 104 (FIG. 14A). The balloon catheter 54 is thus coupled to theintroducer 100. Sliding the entire balloon catheter 54 distally permitsthe irregular contours of the distal extremity thereof to pass safelyacross the valves 106, 110, 112 and into the introducer sheath 70. Theloader 140 remains coupled to the introducer 100 during the valveimplant procedure, and the vent member 182 can be actuated as needed toensure no air remains in the system.

The various components of the balloon catheter 54 will now be describedwith respect to FIGS. 8-12 . The catheter 54 includes the proximalcontrol handle 54 and a plurality of concentric tubes that extenddistally to the soft tip 144. In the exemplary embodiment, fiveconcentric tubes of gradually smaller size connect to or extend into thehandle 150, as seen in FIG. 10B. The handle 150 includes two moldedhalves having a plurality of inner walls and cavities to contain thevarious components.

The handle 150 includes a number of control components and is shown insection in FIG. 9 and exploded in FIGS. 10A and 10B. Specifically, thedeflection actuator 154 in the form of a trigger controls deflection ofthe distal tip of the balloon deflection tube 160, the pusher actuator156 in the form of a slider controls longitudinal movement of the pusherbody 158, and operation of a stopcock 190 permits infusion of fluids toflush a space between the introducer sheath 70 and the pusher body 158.Furthermore, a Y-port 192 at the proximal end of the handle 150 providesa longitudinal passage leading to the luer fitting 142 and an angledpassage leading to the balloon inflation connector 152. An inner tube194 (smallest) having a throughbore extends the length of the ballooncatheter 54 from the luer fitting 142 through the distal soft tip 144(see FIG. 12 ). The inner tube 194 provides a channel for passage of aguidewire, such as shown at 60 in FIG. 3D. The luer fitting 142 also mayprovide an entry point for injection of radiographic contrast mediumthough the inner tube 194, which is useful to check for perivalvularleaks after the prosthetic valve is implanted.

Still with reference to FIGS. 8-10 , and in particular FIG. 9 , aballoon inflation tube 196 (second smallest) surrounds the inner tube194, extending from the Y-port 192 in a distal direction and terminatingwithin the balloon 52. As seen in FIG. 9 , the Y-port 192 includes astepped longitudinal bore having a larger distal portion that sealinglyreceives the balloon inflation tube 196, and a smaller middle portionthat sealingly receives the inner tube 194. The angled passage leadingto the balloon inflation connector 152 fluidly communicates with a spaceoutside of the inner tube 194 that opens to the lumen of the ballooninflation tube 196. With this configuration, fluid injected into theballoon inflation connector 152 passes into and travels the length ofthe balloon inflation tube 196 until it exits from the open distal end198 thereof, within the balloon 52 (as seen in FIG. 12 ). Additionalfluid egress ports (not shown) may be provided in the balloon inflationtube 196 along the length of the balloon 52 for even inflation, and inparticular ports proximal and distal to the prosthetic heart valve 50are beneficial to help expand both ends of the valve at the same rate.

The balloon inflation tube 196 extends through the lumen of the balloondeflection tube 160 (third smallest) which has a proximal end anchoredby a collar 200 fixed within a cavity of the handle 150. The balloondeflection tube 160 has a particular construction that enables flexingalong its length without kinking, and has a deflectable distal tip. Moreparticularly, the balloon deflection tube 160 desirably includes abraided tube along its length to prevent kinking, a coil structure atits distal tip for deflection, and a deflection wire 202 that extendsfrom the proximal end to the coil.

The deflection wire 202 also includes a plug 204 fixed on its proximalend acted on by a rail 206 that slides longitudinally within the handle150. Specifically, the deflection wire 202 passes through an aperture ofa finger 208 on the rail 206, which aperture is smaller than the plug204. The plug 204 is desirably cylindrical and may be constrained withina small guide sleeve 210 held within a cavity of the handle 150. Therail 206 forms part of a trigger assembly and moves with the trigger154. Pulling the trigger 154 to the left from its position in FIGS. 8and 9 will displace the plug 204 to the left, also pulling thedeflection wire 202 to the left, or in a proximal direction. Thedeflection wire 202 in turn attaches to one side of the coil at a distaltip 212 of the balloon deflection tube 160, and pulling on the wire thusdeflects the distal tip, as seen in FIGS. 14D and 14E. Of course byrotating the entire balloon catheter 54 about its axis the deflectingsegment 212 may be steered in any direction. The coil provides bothflexibility and resiliency such that release of tension on thedeflection wire 202 permits the deflecting segment 212 to return to astraight orientation.

The construction of the deflection tube 160 enables a size reductionfrom prior designs that ultimately enables a size reduction of the valve50 and balloon 52. In one embodiment, the deflection tube 160 has adimension no greater than 8 French. The braided proximal portionprovides flexibility and column strength, while the distal coil enablesthe deflection only at the distal end. The distal tip 212 having thecoil structure desirably has a length of about 4 cm. This constructionalso facilitates manufacture, as the braided proximal portion and coilwith attached deflection wire 202 are easily combined using welding orthe like.

The second largest tube is the pusher body 158, which is tubular untilan outwardly flared sleeve 220 on its distal end (see FIGS. 8 and 11 ).A proximal end of the pusher body 158 affixes to a threaded sleeve 222that couples with an internally threaded bore of a slider cap 224, asseen in FIGS. 9 and 10B. One or more passive O-ring seals 226 within thebore of the slider cap 224 permit relative movement of the slider memberover the balloon deflection tube 160 while sealing against blood leakagetherebetween. Desirably, two O-rings 226 sandwich an annular polymer(e.g., nylon) washer 228 to help even out the forces on each of theO-rings and therefore enhance the quality of the fluid seal around theballoon deflection tube 160. Translation of the slider 156 and attachedslider cap 224 along a corresponding longitudinal slot in the handle 150thus displaces the pusher body 158 relative to the handle and to theballoon deflection tube 160. Previous devices included separate handlesand the seal would be positioned within a threaded cap that requiredtightening. The passive nature of the O-ring seal eliminates thetwo-handed tightening operation and also avoids any misalignment of theheart valve 50 once positioned from inadvertent movement of the balloondeflection tube 160.

Moreover, the design of the handle 150 facilitates one-handed operationof the two primary movements of the balloon catheter 54—deflection ofthe distal tip and linear movement of the pusher body 58. The handle 150preferably includes ergonomic ribs 230 on its underside, as seen in FIG.8 , which, coupled with ribs on the slider 156 assist in moving thepusher body 158 along the catheter.

The pusher body 158 slides over the balloon deflection tube 160 as wellas inside of the stationary protective sleeve 162 (the largest tube). Asseen in FIG. 9 , the sleeve 162 affixes into a stepped bore of a housingof the stopcock 190, which in turn attaches to a distal end of thehandle. An O-ring seal 232 held within the stopcock housing (or betweenthe housing and the handle 150) contacts and seals against the exteriorof the moving pusher body 158 and prevents leakage of fluid from theconcentric space between the pusher body 158 and the stationaryprotective sleeve 162. Saline or other such fluid may thus be infused inthrough the stopcock 190 to travel down and flush the concentric spacebetween the pusher body 158 and the stationary protective sleeve 162.

FIG. 11 is an elevational view of the distal end of the balloon catheter54 showing the balloon 52 deflated and its proximal end spaced from thepusher sleeve 220, while FIG. 12 shows the distal end of the ballooncatheter 54 with the balloon 52 inflated.

The inner tube 194 passes through the balloon 52 and terminates at adistal end that is capped by the aforementioned soft tip 144. The softtip 144 facilitates introduction of the balloon catheter 54 and reducestrauma to surrounding tissue. This is particularly important in thepreferred procedure of the present invention where the catheter entersthe apex of the left ventricle and travels through the aortic valve intothe ascending aorta. As was seen in FIG. 3D, the distal tip of thecatheter may extend far enough to enter the aortic arch, and the softtip 144 thus prevents rupture or other abrasion to the surroundingvascular tissue. FIG. 13 also illustrates the open distal end of theinner tube 194 and soft tip 144 through which first a guidewire 62 maybe passed and then radiographic contrast medium may be injected to testvalve sufficiency after implant.

The balloon 52 includes a first cone portion 240, a main cylindricalportion 242, and a second cone portion 244. The prosthetic heart valve50 desirably crimps around the main cylindrical portion 242 for evencylindrical expansion, such as shown in phantom in FIG. 12 . The balloon52 can be formed of nylon, and is rated at a burst pressure of 6-8 atm.In preferred embodiments, the expanded diameter of the balloon rangesfrom about 20 to 28 mm, the particular size depending on the size of theheart valve 50 being implanted.

FIG. 15 is a longitudinal sectional view of a distal end of theexemplary balloon catheter 54 showing a prosthetic heart valve 50crimped over the balloon 52. The heart valve 50 has a shorter lengththan the balloon 52 leaving proximal and distal exposed portionsthereof.

The balloon 52 is folded in a way that enhances visualization of thevalve during implant. Specifically, certain conventional foldingtechniques resulted in wrinkling of the balloon 52. For example, acommon way to fold a catheter balloon is to first form a trifold andthen wrapping the leaves of the trifold around the balloon catheteraxis. Folding techniques like this often leave wrinkles or ripples evenif done carefully. Such irregularities show up on echocardiography,which can interfere with precise location of the proximal and distalends of the valve 50 relative to the implant site. The balloon 52 of thepresent invention on the other hand is folded in a manner that reducesif not eliminates irregularities that show up on echocardiography, thusenhancing the ability to properly locate the heart valve 50 at theaortic annulus.

FIG. 16 is a radial section of the folded balloon of FIG. 15 , and showsfour leaves 250 of the balloon 52 folding in a clockwise manner aroundthe inner tubes 194, 196, though of course the direction that the leavesare wrapped is not critical. FIG. 17 illustrates the leaves 250 prior tofolding. The leaves 250 extend longitudinally along the balloon 52 andcomprise even circumferential spans of the balloon 52. By carefulselection of the radial dimension of each leaf 250, the resultingwrapped structure in FIG. 16 is minimized for that size of balloon, andensuring even circumferential wrapping rates results in longitudinallines in the wrapped structure. The longitudinal fold lines contrastunder fluoroscopy with the radial ends of the valve 50, thus ensuring aclear view of the valve. Moreover, the longitudinal fold lines contrastwith marker bands on the balloon and the pusher, as explained above.There may be four or more, possibly 6-8 folds or pleats pre-formed inthe balloon which also facilitate deflation and removal through thevalve and introducer.

In use, the present invention provides a novel and effective way forimplanting a prosthetic heart valve 50 in the aortic annulus. The stepsof the procedure have been described above with respect to FIGS. 1-3 ,at least as far as the final implantation steps. A description of theadvantageous use of the exemplary balloon catheter 54 and introducer 100in performing the entire procedure will now be provided with referenceto FIGS. 13 and 14A-14E, which are in situ views of the system withoutthe valve 50.

First, as mentioned above, the physician determines the size of thepatient's annulus. This can be done physically by creating the incision20 and puncture 32 (FIGS. 1 and 2A) in the left ventricular apex, andinserting a sizing tool into the aortic annulus. However, the puncture32 may not be large enough to pass a conventional sizer, and analternative technique such as echocardiography or other such imagingsystem may be utilized.

Next, the balloon catheter 54, introducer 100, loader 140, andprosthetic heart valve 50 are selected, and prepared for use by removingthem from any packaging and rinsing or sterilizing as needed. Apre-dilation step as described above with respect to FIGS. 2A-2B may beperformed to enlarge or crack existing calcification in the aorticannulus.

The process of crimping the prosthetic heart valve 50 over the balloon52 may be accomplished in a number of ways, and there are suitabledevices on the market for crimping balloon-expanding stents overballoons. In a preferred embodiment, a device having a compressingmechanism that works like the aperture iris of a camera is utilized. Insuch a device, multiple continuous segments around the periphery of theprosthetic heart valve 50 close separately but in concert so thatuniform inward pressure is exerted on the heart valve. The devicestypically operate manually.

Subsequently, the aforementioned pusher body 158 and flared sleeve 220are advanced distally over the proximal end of the balloon 52, such asseen in FIG. 13 . The loader 140 is then secured over the distal end ofthe balloon catheter 54, including the assembly of the balloon 52 andprosthetic valve (not shown).

At this point, or at the same time as balloon catheter preparation, theintroducer 100 is positioned within the left ventricle as seen in FIG.3A. Again, the purse-string sutures 44 maintain a fluid tight sealaround the introducer sheath 70. During the entire procedure the heartmay continue beating. The physician inserts the distal nose 174 of theloader 140 into the proximal end cap 104 of the introducer 100 andbottoms the loader out such that the cantilevered fingers 176 engage theflanged nipple 105 of the introducer, as seen in FIG. 14A. At thispoint, the balloon catheter 54 is ready for introduction in the body.

The pusher body 158 and pusher sleeve 220, as well as the stationaryprotective sleeve 162, facilitate advancement of the deflecting segment212 and attached balloon 52 having the valve 50 crimped thereon throughthe introducer sheath 70 and its valves 106, 110, 112. In particular,the flared pusher sleeve 220 surrounds the deflecting segment 212 and aproximal portion of the balloon 52 during passage through the introducersheath 70. The pusher sleeve 220 secures the crimped valve from movementrelative to the balloon 52. Eventually, proximal retraction of thepusher body 158 relative to the balloon deflection tube 160 frees thedeflecting segment 212 for angled movement, and the balloon 52 forexpansion.

The physician then distally advances the balloon catheter 54 withrespect to the loader 140 and introducer 100 into a position such asthat shown in FIG. 14B. In this state, the balloon 52 with valve may beadvanced to its eventual implant position using echocardiography, forexample.

The physician then retracts the pusher sleeve 220 from the deflectingsegment 212 and the proximal portion of the balloon 52, as seen in FIG.14C, by simply sliding back the pusher actuator 156 on the handle 150.The stationary protective sleeve 162 around the pusher body 158 servesto decouple movement of the pusher from the valves of the introducer,thus reducing friction on the pusher. Also, the one-handed operation ofsliding back the pusher actuator 156 while grasping the handle 150greatly reduces the chance of misalignment of the valve position.

The physician may further advance and angle the balloon 52 until itreaches the position shown in FIG. 3C. The entire operation isvisualized using radiographic markers and fluoroscopy, and the precisepositioning of the balloon 52 and prosthetic valve 50 mounted thereon isaccomplished by axial movement and rotation of the catheter 54 coupledwith angular changes of the deflecting segment 212, as seen in FIG. 14D.Specifically, as the prosthetic valve 54 advances it is aligned as muchas possible along the flow axis of the native aortic valve AV by grossmovement of the catheter 54 and slight changes in its angularorientation by tensioning the deflecting wire 202 with the deflectionactuator 154.

As mentioned above, the deflection wire 202 (FIG. 10B) extends from thehandle 150 along the balloon deflection tube 160 and terminates at thedeflecting segment 212, and preferably at a distal end of a coil springtherein (not shown). Pulling the deflection wire 202 causes thedeflecting segment 212 to be pulled to the side of attachment of thewire, thus deflecting the distal end of the catheter and balloon 52, asin FIG. 14D.

Ultimately, the valve 50 is positioned correctly as in FIG. 3C takingcare that the valve 50 is not liable to block either of the coronaryostia 80 when expanded. Saline mixed with contrast is then injectedthrough the balloon inflation connector 152 which passes through thelength of the balloon inflation tube 196 to fill the balloon 52, as seenin FIG. 14E. The balloon 52 is of a type that has a maximum expandeddiameter which has previously been selected to properly expand theprosthetic heart valve 52 to its optimum diameter in contact with thesurrounding aortic valve AV, and calcified leaflets if they remain inplace. The step is illustrated in FIG. 3D. The balloon 52 expands theprosthetic heart valve 50 to implant it in the annulus, after which theballoon is deflated and removed from within the valve.

Subsequently, radiographic contrast medium may be injected from theproximal luer connection 142 of the balloon catheter 54 to egressthrough the distal soft tip 144 and test the efficacy of thejust-implanted prosthetic valve 50. If the valve is properlyfunctioning, the balloon catheter 54 is withdrawn into the introducersheath 70, which is removed from the puncture 32. The purse-stringsutures 44 are closed up to seal the puncture 32.

Once again, the delivery system described herein is particularlywell-suited for an antegrade, transapical approach, partly because ofits relatively short length. With reference to FIG. 4A, the entirelength of the introducer 100 is approximately 13 inches (33 cm), whilethe length of the sheath 70 that may extend within the body is betweenabout 20-24 cm. The portion of the balloon catheter 54 that extends intothe introducer 100 (that is, the portion of the balloon catheter fromthe distal soft tip 144 to approximately the deflection handle 154) ispreferably no more than about 24 inches (61 cm), which permits about 11inches (28 cm) of the balloon catheter to extend beyond the introducerdistal tip 72 (see FIG. 4 ). It should be noted that the relativelyshort length of the delivery system is unsuited for a longer, morecircuitous approach through the peripheral vasculature, such as shown inco-pending U.S. Patent Publication No. 2007-0005131 to Taylor. Also, thesteering mechanism is provided on the balloon catheter 54 itself, ratherthan on a secondary catheter used for guiding the balloon catheter, asis done in U.S. Patent Publication No. 2007-0005131. The short length ofthe balloon catheter and the ability to directly manipulate it greatlyenhances successful positioning of the prosthetic heart in the aorticannulus.

While the invention has been described in its preferred embodiments, itis to be understood that the words which have been used are words ofdescription and not of limitation. Therefore, changes may be made withinthe appended claims without departing from the true scope of theinvention.

What is claimed is:
 1. A system for delivery of a prosthetic heart valveto a beating heart, comprising: a delivery catheter having a distalballoon of sufficient diameter to expand a heart valve crimped thereon,wherein the delivery catheter has a proximal control handle with aplurality of concentric tubes extending distally from within the controlhandle and at least one actuator on the exterior of the control handlefor moving one of the tubes axially; an introducer that receives thedelivery catheter therethrough and has an elongated tubular sheathextending distally from a proximal housing containing at least oneintroducer valve for fluidly sealing around devices passed therethrough,the introducer having a length sufficient to extend from outside apatient through an intercostal incision and into the left ventricle ofthe patient; and a tubular loader defining a throughbore that receives adistal portion of the delivery catheter, and includes structure forengaging mating structure on the proximal housing of the introducer anda distal nose that extends through and opens the at least one introducervalve and facilitates passage therethrough of the delivery catheter, theloader having a proximal housing with a loader seal for fluidly sealingaround the delivery catheter, and a single-handed vent for aspiratingair from within the loader housing.
 2. The system of claim 1, whereinthe heart valve is crimped on the catheter tube just distal to adeflectable portion thereof, wherein one of the concentric tubesextending from within the control handle includes the catheter tube, andthe proximal control handle has mounted on an exterior thereof both adeflection actuator for deflecting the deflectable portion of thecatheter tube via a deflection pull wire and an actuator for moving oneof the concentric tubes axially relative to the other concentric tubes.3. The system of claim 2, wherein the deflection actuator and theactuator are located so as to enable one handed operation of both. 4.The system of claim 3, wherein the deflection actuator is a trigger andthe actuator is a slider.
 5. The system of claim 2, wherein thedeflectable portion comprises a braided structure with a distal coil towhich the deflection pull wire attaches.
 6. The system of claim 1,wherein the proximal housing of the loader has a resilient vent membertherein, and the single-handed vent comprises a vent button thatprojects through an aperture in the side of the proximal housing and ispositioned such that inward depression of the vent button causesdeformation of the vent member which in turn opens the loaderthroughbore to the atmosphere.
 7. The system of claim 6, wherein thereare two vent buttons on opposite sides of the proximal housing of theloader that each engage the resilient vent member.
 8. The system ofclaim 1, wherein the sheath includes a proximal segment extending alength of at least one half a total length L of the sheath and having afirst stiffness, and a distal section having a length I of one half orless of the total length L of the sheath that has a second stiffnessdifferent than the first stiffness.
 9. The system of claim 1, whereinthe delivery catheter tube has a fluoroscopically-visible marker locatedproximal to the prosthetic heart valve crimped on the distal balloon,and the introducer sheath having a fluoroscopically-visible marker on adistal tip distinguishable from the marker of the delivery cathetertube.
 10. The system of claim 9, wherein the balloon in a deflatedconfiguration is folded in a manner that leaves only longitudinal foldlines to provide good fluoroscopic contrast with the marker of thedelivery catheter tube and the marker of the introducer sheath.
 11. Asystem for delivery of a prosthetic heart valve to a beating heart,comprising: a delivery catheter having a distal balloon of sufficientdiameter to expand a heart valve crimped thereon, wherein the deliverycatheter has a proximal control handle with a plurality of concentrictubes extending distally from within the control handle and at least oneactuator on the exterior of the control handle for moving one of thetubes axially; an introducer that receives the delivery cathetertherethrough and has an elongated tubular sheath extending distally froma proximal housing containing at least one introducer valve for fluidlysealing around devices passed therethrough, the sheath including aproximal segment extending a length of at least one half a total lengthL of the sheath and having a first stiffness, and a distal sectionhaving a length I of one half or less of the total length L of thesheath that has a second stiffness different than the first stiffness,the introducer having a length sufficient to extend from outside apatient through an intercostal incision and into the left ventricle ofthe patient.
 12. The system of claim 11, wherein the introducer sheathis no more than 13 inches (33 cm) long.
 13. The system of claim 11,wherein the length I ranges between about 4-12 cm.
 14. The system ofclaim 11, wherein the length L is at least 24 cm, and the length Iranges between about 6-9 cm.
 15. The system of claim 11, wherein thetubular sheath has an inner liner and a reinforcing coil that bothextend the entire length, and at least two sections of outer tubes inseries having different durometers that create the differing stiffnessesof the sheath.
 16. The system of claim 11, wherein the heart valve iscrimped on the catheter tube just distal to a deflectable portionthereof, wherein one of the concentric tubes extending from within thecontrol handle includes the catheter tube, and the proximal controlhandle has mounted on an exterior thereof both a deflection actuator fordeflecting the deflectable portion of the catheter tube via a deflectionpull wire and an actuator for moving one of the concentric tubes axiallyrelative to the other concentric tubes.
 17. The system of claim 16,wherein the deflection actuator and the actuator are located so as toenable one handed operation of both.
 18. The system of claim 17, whereinthe deflection actuator is a trigger and the actuator is a slider. 19.The system of claim 16, wherein the deflectable portion comprises abraided structure with a distal coil to which the deflection pull wireattaches.
 20. The system of claim 11, further including a tubular loaderdefining a throughbore that receives a distal portion of the deliverycatheter, and includes structure for engaging mating structure on theproximal housing of the introducer and a distal nose that extendsthrough and opens the at least one introducer valve and facilitatespassage therethrough of the delivery catheter, the loader having aproximal housing with a loader seal for fluidly sealing around thedelivery catheter, and a single-handed vent for aspirating air fromwithin the loader housing.